2. Field of the Invention
The present invention is related to removing pollutants from exhaust gases and, more particularly, to removing chlorinated polycyclic aromatic hydrocarbons from an exhaust gas such as that produced by a municipal solid waste incinerator.
2. Description of the Related Art
Within the last one to two decades, toxic substances such as dioxins and furans have been found in the exhausts of municipal solid waste incinerators. In addition, these substances as well as polychlorinated biphenyls (PCBs), are often present at toxic waste sites. Disposal of such substances which are present in exhaust gases and at toxic waste sites, as well as under other circumstances, is a serious problem because these substances are toxic, even in minute amounts, and are very stable. Therefore, some means for decomposing such substances and creating nontoxic byproducts is much sought after. Over the last two decades several studies have been conducted which indicate that many of the toxic substances identified in the exhaust of municipal waste incinerators are broken down at temperatures somewhere between 600.degree. C. and 1300.degree. C. provided they are exposed to such temperatures for a minimum period of time which may be as long as 2 and one-half seconds. All known techniques of providing thermal destruction of aromatic hydrocarbons such as PCBs, dioxins, furans and polycyclic hydrocarbons, use expensive refractory materials and large amounts of energy to produce the required temperatures for the flow rates of interest.